Pavel S
mbed OS5
Fork of
UIPEthernet
by 
Zoltan Hudak
Diff: utility/uip.c
- Revision:
- 1:01c2344f98a3
- Parent:
- 0:5350a66d5279
diff -r 5350a66d5279 -r 01c2344f98a3 utility/uip.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/utility/uip.c Thu Nov 20 21:26:54 2014 +0000
@@ -0,0 +1,2054 @@
+#define DEBUG_PRINTF(...) /*printf(__VA_ARGS__)*/
+
+/**
+ * \defgroup uip The uIP TCP/IP stack
+ * @{
+ *
+ * uIP is an implementation of the TCP/IP protocol stack intended for
+ * small 8-bit and 16-bit microcontrollers.
+ *
+ * uIP provides the necessary protocols for Internet communication,
+ * with a very small code footprint and RAM requirements - the uIP
+ * code size is on the order of a few kilobytes and RAM usage is on
+ * the order of a few hundred bytes.
+ */
+
+/**
+ * \file
+ * The uIP TCP/IP stack code.
+ * \author Adam Dunkels <adam@dunkels.com>
+ */
+/*
+ * Copyright (c) 2001-2003, Adam Dunkels.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote
+ * products derived from this software without specific prior
+ * written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
+ * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
+ * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This file is part of the uIP TCP/IP stack.
+ *
+ * $Id: uip.c,v 1.65 2006/06/11 21:46:39 adam Exp $
+ *
+ */
+/*
+ * uIP is a small implementation of the IP, UDP and TCP protocols (as
+ * well as some basic ICMP stuff). The implementation couples the IP,
+ * UDP, TCP and the application layers very tightly. To keep the size
+ * of the compiled code down, this code frequently uses the goto
+ * statement. While it would be possible to break the uip_process()
+ * function into many smaller functions, this would increase the code
+ * size because of the overhead of parameter passing and the fact that
+ * the optimier would not be as efficient.
+ *
+ * The principle is that we have a small buffer, called the uip_buf,
+ * in which the device driver puts an incoming packet. The TCP/IP
+ * stack parses the headers in the packet, and calls the
+ * application. If the remote host has sent data to the application,
+ * this data is present in the uip_buf and the application read the
+ * data from there. It is up to the application to put this data into
+ * a byte stream if needed. The application will not be fed with data
+ * that is out of sequence.
+ *
+ * If the application whishes to send data to the peer, it should put
+ * its data into the uip_buf. The uip_appdata pointer points to the
+ * first available byte. The TCP/IP stack will calculate the
+ * checksums, and fill in the necessary header fields and finally send
+ * the packet back to the peer.
+*/
+#include "uip.h"
+#include "uipopt.h"
+#include "uip_arch.h"
+
+#if UIP_CONF_IPV6
+ #include "uip-neighbor.h"
+#endif /* UIP_CONF_IPV6 */
+
+#include <string.h>
+
+/*---------------------------------------------------------------------------*/
+
+/* Variable definitions. */
+/* The IP address of this host. If it is defined to be fixed (by
+ setting UIP_FIXEDADDR to 1 in uipopt.h), the address is set
+ here. Otherwise, the address */
+#if UIP_FIXEDADDR > 0
+const uip_ipaddr_t uip_hostaddr = { HTONS((UIP_IPADDR0 << 8) | UIP_IPADDR1), HTONS
+ ((UIP_IPADDR2 << 8) | UIP_IPADDR3) };
+const uip_ipaddr_t uip_draddr =
+{
+ HTONS((UIP_DRIPADDR0 << 8) | UIP_DRIPADDR1),
+ HTONS((UIP_DRIPADDR2 << 8) | UIP_DRIPADDR3)
+};
+const uip_ipaddr_t uip_netmask =
+{
+ HTONS((UIP_NETMASK0 << 8) | UIP_NETMASK1),
+ HTONS((UIP_NETMASK2 << 8) | UIP_NETMASK3)
+};
+#else
+uip_ipaddr_t uip_hostaddr, uip_draddr, uip_netmask;
+#endif /* UIP_FIXEDADDR */
+
+static const uip_ipaddr_t all_ones_addr =
+#if UIP_CONF_IPV6
+{ 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff };
+#else /* UIP_CONF_IPV6 */
+{
+ 0xffff, 0xffff
+};
+#endif /* UIP_CONF_IPV6 */
+static const uip_ipaddr_t all_zeroes_addr =
+#if UIP_CONF_IPV6
+{ 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000 };
+#else /* UIP_CONF_IPV6 */
+{
+ 0x0000, 0x0000
+};
+#endif /* UIP_CONF_IPV6 */
+
+#if UIP_FIXEDETHADDR
+const struct uip_eth_addr uip_ethaddr =
+{
+ { UIP_ETHADDR0, UIP_ETHADDR1, UIP_ETHADDR2, UIP_ETHADDR3, UIP_ETHADDR4, UIP_ETHADDR5 }
+};
+#else
+struct uip_eth_addr uip_ethaddr = { { 0, 0, 0, 0, 0, 0 } };
+#endif
+#ifndef UIP_CONF_EXTERNAL_BUFFER
+u8_t uip_buf[UIP_BUFSIZE + 2]; /* The packet buffer that contains
+ incoming packets. */
+#endif /* UIP_CONF_EXTERNAL_BUFFER */
+
+void* uip_appdata; /* The uip_appdata pointer points to
+ application data. */
+void* uip_sappdata; /* The uip_appdata pointer points to
+ the application data which is to
+ be sent. */
+#if UIP_URGDATA > 0
+void* uip_urgdata; /* The uip_urgdata pointer points to
+ urgent data (out-of-band data), if
+ present. */
+u16_t uip_urglen, uip_surglen;
+#endif /* UIP_URGDATA > 0 */
+
+u16_t uip_len, uip_slen;
+
+/* The uip_len is either 8 or 16 bits,
+ depending on the maximum packet
+ size. */
+u8_t uip_flags; /* The uip_flags variable is used for
+ communication between the TCP/IP stack
+ and the application program. */
+struct uip_conn* uip_conn; /* uip_conn always points to the current
+ connection. */
+
+struct uip_conn uip_conns[UIP_CONNS];
+
+/* The uip_conns array holds all TCP
+ connections. */
+u16_t uip_listenports[UIP_LISTENPORTS];
+
+/* The uip_listenports list all currently
+ listning ports. */
+#if UIP_UDP
+struct uip_udp_conn* uip_udp_conn;
+struct uip_udp_conn uip_udp_conns[UIP_UDP_CONNS];
+#endif /* UIP_UDP */
+
+static u16_t ipid; /* Ths ipid variable is an increasing
+ number that is used for the IP ID
+ field. */
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+void uip_setipid(u16_t id) {
+ ipid = id;
+}
+
+static u8_t iss[4]; /* The iss variable is used for the TCP
+ initial sequence number. */
+
+#if UIP_ACTIVE_OPEN
+static u16_t lastport; /* Keeps track of the last port used for
+ a new connection. */
+#endif /* UIP_ACTIVE_OPEN */
+
+/* Temporary variables. */
+
+u8_t uip_acc32[4];
+static u8_t c, opt;
+static u16_t tmp16;
+
+/* Structures and definitions. */
+
+#define TCP_FIN 0x01
+#define TCP_SYN 0x02
+#define TCP_RST 0x04
+#define TCP_PSH 0x08
+#define TCP_ACK 0x10
+#define TCP_URG 0x20
+#define TCP_CTL 0x3f
+
+#define TCP_OPT_END 0 /* End of TCP options list */
+
+#define TCP_OPT_NOOP 1 /* "No-operation" TCP option */
+
+#define TCP_OPT_MSS 2 /* Maximum segment size TCP option */
+
+#define TCP_OPT_MSS_LEN 4 /* Length of TCP MSS option. */
+
+#define ICMP_ECHO_REPLY 0
+#define ICMP_ECHO 8
+
+#define ICMP6_ECHO_REPLY 129
+#define ICMP6_ECHO 128
+#define ICMP6_NEIGHBOR_SOLICITATION 135
+#define ICMP6_NEIGHBOR_ADVERTISEMENT 136
+
+#define ICMP6_FLAG_S (1 << 6)
+#define ICMP6_OPTION_SOURCE_LINK_ADDRESS 1
+#define ICMP6_OPTION_TARGET_LINK_ADDRESS 2
+
+/* Macros. */
+
+#define BUF ((struct uip_tcpip_hdr*) &uip_buf[UIP_LLH_LEN])
+#define FBUF ((struct uip_tcpip_hdr*) &uip_reassbuf[0])
+#define ICMPBUF ((struct uip_icmpip_hdr*) &uip_buf[UIP_LLH_LEN])
+#define UDPBUF ((struct uip_udpip_hdr*) &uip_buf[UIP_LLH_LEN])
+#if UIP_STATISTICS == 1
+struct uip_stats uip_stat;
+ #define UIP_STAT(s) s
+#else
+ #define UIP_STAT(s)
+#endif /* UIP_STATISTICS == 1 */
+
+#if UIP_LOGGING == 1
+ #include <stdio.h>
+void uip_log(char* msg);
+ #define UIP_LOG(m) uip_log(m)
+#else
+ #define UIP_LOG(m)
+#endif /* UIP_LOGGING == 1 */
+
+#if !UIP_ARCH_ADD32
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+void uip_add32(u8_t* op32, u16_t op16) {
+ uip_acc32[3] = op32[3] + (op16 & 0xff);
+ uip_acc32[2] = op32[2] + (op16 >> 8);
+ uip_acc32[1] = op32[1];
+ uip_acc32[0] = op32[0];
+
+ if(uip_acc32[2] < (op16 >> 8)) {
+ ++uip_acc32[1];
+ if(uip_acc32[1] == 0) {
+ ++uip_acc32[0];
+ }
+ }
+
+ if(uip_acc32[3] < (op16 & 0xff)) {
+ ++uip_acc32[2];
+ if(uip_acc32[2] == 0) {
+ ++uip_acc32[1];
+ if(uip_acc32[1] == 0) {
+ ++uip_acc32[0];
+ }
+ }
+ }
+}
+#endif /* UIP_ARCH_ADD32 */
+
+#if !UIP_ARCH_CHKSUM
+
+/*---------------------------------------------------------------------------*/
+static u16_t chksum(u16_t sum, const u8_t* data, u16_t len) {
+ u16_t t;
+ const u8_t* dataptr;
+ const u8_t* last_byte;
+
+ dataptr = data;
+ last_byte = data + len - 1;
+
+ while(dataptr < last_byte) {
+
+ /* At least two more bytes */
+ t = (dataptr[0] << 8) + dataptr[1];
+ sum += t;
+ if(sum < t) {
+ sum++; /* carry */
+ }
+
+ dataptr += 2;
+ }
+
+ if(dataptr == last_byte) {
+ t = (dataptr[0] << 8) + 0;
+ sum += t;
+ if(sum < t) {
+ sum++; /* carry */
+ }
+ }
+
+ /* Return sum in host byte order. */
+ return sum;
+}
+
+/*---------------------------------------------------------------------------*/
+u16_t uip_chksum(u16_t* data, u16_t len) {
+ return htons(chksum(0, (u8_t*)data, len));
+}
+
+/*---------------------------------------------------------------------------*/
+ #ifndef UIP_ARCH_IPCHKSUM
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+u16_t uip_ipchksum(void) {
+ u16_t sum;
+
+ sum = chksum(0, &uip_buf[UIP_LLH_LEN], UIP_IPH_LEN);
+ DEBUG_PRINTF("uip_ipchksum: sum 0x%04x\n", sum);
+ return(sum == 0) ? 0xffff : htons(sum);
+}
+ #endif
+
+/*---------------------------------------------------------------------------*/
+static u16_t upper_layer_chksum(u8_t proto) {
+ u16_t upper_layer_len;
+ u16_t sum;
+
+ #if UIP_CONF_IPV6
+ upper_layer_len = (((u16_t) (BUF->len[0]) << 8) + BUF->len[1]);
+ #else /* UIP_CONF_IPV6 */
+ upper_layer_len = (((u16_t) (BUF->len[0]) << 8) + BUF->len[1]) - UIP_IPH_LEN;
+ #endif /* UIP_CONF_IPV6 */
+
+ /* First sum pseudoheader. */
+
+ /* IP protocol and length fields. This addition cannot carry. */
+ sum = upper_layer_len + proto;
+
+ /* Sum IP source and destination addresses. */
+ sum = chksum(sum, (u8_t*) &BUF->srcipaddr[0], 2 * sizeof(uip_ipaddr_t));
+
+ /* Sum TCP header and data. */
+ sum = chksum(sum, &uip_buf[UIP_IPH_LEN + UIP_LLH_LEN], upper_layer_len);
+
+ return(sum == 0) ? 0xffff : htons(sum);
+}
+
+/*---------------------------------------------------------------------------*/
+ #if UIP_CONF_IPV6
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+u16_t uip_icmp6chksum(void) {
+ return upper_layer_chksum(UIP_PROTO_ICMP6);
+}
+ #endif /* UIP_CONF_IPV6 */
+
+/*---------------------------------------------------------------------------*/
+u16_t uip_tcpchksum(void) {
+ return upper_layer_chksum(UIP_PROTO_TCP);
+}
+
+/*---------------------------------------------------------------------------*/
+ #if UIP_UDP_CHECKSUMS
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+u16_t uip_udpchksum(void) {
+ return upper_layer_chksum(UIP_PROTO_UDP);
+}
+ #endif /* UIP_UDP_CHECKSUMS */
+#endif /* UIP_ARCH_CHKSUM */
+
+/*---------------------------------------------------------------------------*/
+void uip_init(void) {
+ for(c = 0; c < UIP_LISTENPORTS; ++c) {
+ uip_listenports[c] = 0;
+ }
+
+ for(c = 0; c < UIP_CONNS; ++c) {
+ uip_conns[c].tcpstateflags = UIP_CLOSED;
+ }
+
+#if UIP_ACTIVE_OPEN
+ lastport = 1024;
+#endif /* UIP_ACTIVE_OPEN */
+
+#if UIP_UDP
+ for(c = 0; c < UIP_UDP_CONNS; ++c) {
+ uip_udp_conns[c].lport = 0;
+ }
+#endif /* UIP_UDP */
+
+ /* IPv4 initialization. */
+
+#if UIP_FIXEDADDR == 0
+ /* uip_hostaddr[0] = uip_hostaddr[1] = 0;*/
+#endif /* UIP_FIXEDADDR */
+}
+
+/*---------------------------------------------------------------------------*/
+#if UIP_ACTIVE_OPEN
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+struct uip_conn* uip_connect(uip_ipaddr_t* ripaddr, u16_t rport) {
+ register struct uip_conn* conn, *cconn;
+
+ /* Find an unused local port. */
+
+again:
+ ++lastport;
+
+ if(lastport >= 32000) {
+ lastport = 4096;
+ }
+
+ /* Check if this port is already in use, and if so try to find
+ another one. */
+ for(c = 0; c < UIP_CONNS; ++c) {
+ conn = &uip_conns[c];
+ if(conn->tcpstateflags != UIP_CLOSED && conn->lport == htons(lastport)) {
+ goto again;
+ }
+ }
+
+ conn = 0;
+ for(c = 0; c < UIP_CONNS; ++c) {
+ cconn = &uip_conns[c];
+ if(cconn->tcpstateflags == UIP_CLOSED) {
+ conn = cconn;
+ break;
+ }
+
+ if(cconn->tcpstateflags == UIP_TIME_WAIT) {
+ if(conn == 0 || cconn->timer > conn->timer) {
+ conn = cconn;
+ }
+ }
+ }
+
+ if(conn == 0) {
+ return 0;
+ }
+
+ conn->tcpstateflags = UIP_SYN_SENT;
+
+ conn->snd_nxt[0] = iss[0];
+ conn->snd_nxt[1] = iss[1];
+ conn->snd_nxt[2] = iss[2];
+ conn->snd_nxt[3] = iss[3];
+
+ conn->initialmss = conn->mss = UIP_TCP_MSS;
+
+ conn->len = 1; /* TCP length of the SYN is one. */
+ conn->nrtx = 0;
+ conn->timer = 1; /* Send the SYN next time around. */
+ conn->rto = UIP_RTO;
+ conn->sa = 0;
+ conn->sv = 16; /* Initial value of the RTT variance. */
+ conn->lport = htons(lastport);
+ conn->rport = rport;
+ uip_ipaddr_copy(&conn->ripaddr, ripaddr);
+
+ return conn;
+}
+#endif /* UIP_ACTIVE_OPEN */
+
+/*---------------------------------------------------------------------------*/
+
+#if UIP_UDP
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+struct uip_udp_conn* uip_udp_new(uip_ipaddr_t* ripaddr, u16_t rport) {
+ register struct uip_udp_conn* conn;
+
+ /* Find an unused local port. */
+
+again:
+ ++lastport;
+
+ if(lastport >= 32000) {
+ lastport = 4096;
+ }
+
+ for(c = 0; c < UIP_UDP_CONNS; ++c) {
+ if(uip_udp_conns[c].lport == htons(lastport)) {
+ goto again;
+ }
+ }
+
+ conn = 0;
+ for(c = 0; c < UIP_UDP_CONNS; ++c) {
+ if(uip_udp_conns[c].lport == 0) {
+ conn = &uip_udp_conns[c];
+ break;
+ }
+ }
+
+ if(conn == 0) {
+ return 0;
+ }
+
+ conn->lport = HTONS(lastport);
+ conn->rport = rport;
+ if(ripaddr == NULL) {
+ memset(conn->ripaddr, 0, sizeof(uip_ipaddr_t));
+ }
+ else {
+ uip_ipaddr_copy(&conn->ripaddr, ripaddr);
+ }
+
+ conn->ttl = UIP_TTL;
+
+ return conn;
+}
+#endif /* UIP_UDP */
+
+/*---------------------------------------------------------------------------*/
+void uip_unlisten(u16_t port) {
+ for(c = 0; c < UIP_LISTENPORTS; ++c) {
+ if(uip_listenports[c] == port) {
+ uip_listenports[c] = 0;
+ return;
+ }
+ }
+}
+
+/*---------------------------------------------------------------------------*/
+void uip_listen(u16_t port) {
+ for(c = 0; c < UIP_LISTENPORTS; ++c) {
+ if(uip_listenports[c] == 0) {
+ uip_listenports[c] = port;
+ return;
+ }
+ }
+}
+
+/*---------------------------------------------------------------------------*/
+/* XXX: IP fragment reassembly: not well-tested. */
+#if UIP_REASSEMBLY && !UIP_CONF_IPV6
+ #define UIP_REASS_BUFSIZE (UIP_BUFSIZE - UIP_LLH_LEN)
+static u8_t uip_reassbuf[UIP_REASS_BUFSIZE];
+static u8_t uip_reassbitmap[UIP_REASS_BUFSIZE / (8 * 8)];
+static const u8_t bitmap_bits[8] = { 0xff, 0x7f, 0x3f, 0x1f, 0x0f, 0x07, 0x03, 0x01 };
+static u16_t uip_reasslen;
+static u8_t uip_reassflags;
+ #define UIP_REASS_FLAG_LASTFRAG 0x01
+static u8_t uip_reasstmr;
+
+ #define IP_MF 0x20
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+static u8_t uip_reass(void) {
+ u16_t offset, len;
+ u16_t i;
+
+ /* If ip_reasstmr is zero, no packet is present in the buffer, so we
+ write the IP header of the fragment into the reassembly
+ buffer. The timer is updated with the maximum age. */
+
+ if(uip_reasstmr == 0) {
+ memcpy(uip_reassbuf, &BUF->vhl, UIP_IPH_LEN);
+ uip_reasstmr = UIP_REASS_MAXAGE;
+ uip_reassflags = 0;
+
+ /* Clear the bitmap. */
+ memset(uip_reassbitmap, 0, sizeof(uip_reassbitmap));
+ }
+
+ /* Check if the incoming fragment matches the one currently present
+ in the reasembly buffer. If so, we proceed with copying the
+ fragment into the buffer. */
+ if
+ (
+ BUF->srcipaddr[0] == FBUF->srcipaddr[0]
+ && BUF->srcipaddr[1] == FBUF->srcipaddr[1]
+ && BUF->destipaddr[0] == FBUF->destipaddr[0]
+ && BUF->destipaddr[1] == FBUF->destipaddr[1]
+ && BUF->ipid[0] == FBUF->ipid[0]
+ && BUF->ipid[1] == FBUF->ipid[1]
+ ) {
+ len = (BUF->len[0] << 8) + BUF->len[1] - (BUF->vhl & 0x0f) * 4;
+ offset = (((BUF->ipoffset[0] & 0x3f) << 8) + BUF->ipoffset[1]) * 8;
+
+ /* If the offset or the offset + fragment length overflows the
+ reassembly buffer, we discard the entire packet. */
+ if(offset > UIP_REASS_BUFSIZE || offset + len > UIP_REASS_BUFSIZE) {
+ uip_reasstmr = 0;
+ goto nullreturn;
+ }
+
+ /* Copy the fragment into the reassembly buffer, at the right
+ offset. */
+ memcpy(&uip_reassbuf[UIP_IPH_LEN + offset], (char*)BUF + (int)((BUF->vhl & 0x0f) * 4), len);
+
+ /* Update the bitmap. */
+ if(offset / (8 * 8) == (offset + len) / (8 * 8)) {
+
+ /* If the two endpoints are in the same byte, we only update
+ that byte. */
+ uip_reassbitmap[offset / (8 * 8)] |= bitmap_bits[(offset / 8) & 7] &~bitmap_bits[((offset + len) / 8) & 7];
+ }
+ else {
+
+ /* If the two endpoints are in different bytes, we update the
+ bytes in the endpoints and fill the stuff inbetween with
+ 0xff. */
+ uip_reassbitmap[offset / (8 * 8)] |= bitmap_bits[(offset / 8) & 7];
+ for(i = 1 + offset / (8 * 8); i < (offset + len) / (8 * 8); ++i) {
+ uip_reassbitmap[i] = 0xff;
+ }
+
+ uip_reassbitmap[(offset + len) / (8 * 8)] |= ~bitmap_bits[((offset + len) / 8) & 7];
+ }
+
+ /* If this fragment has the More Fragments flag set to zero, we
+ know that this is the last fragment, so we can calculate the
+ size of the entire packet. We also set the
+ IP_REASS_FLAG_LASTFRAG flag to indicate that we have received
+ the final fragment. */
+ if((BUF->ipoffset[0] & IP_MF) == 0) {
+ uip_reassflags |= UIP_REASS_FLAG_LASTFRAG;
+ uip_reasslen = offset + len;
+ }
+
+ /* Finally, we check if we have a full packet in the buffer. We do
+ this by checking if we have the last fragment and if all bits
+ in the bitmap are set. */
+ if(uip_reassflags & UIP_REASS_FLAG_LASTFRAG) {
+
+ /* Check all bytes up to and including all but the last byte in
+ the bitmap. */
+ for(i = 0; i < uip_reasslen / (8 * 8) - 1; ++i) {
+ if(uip_reassbitmap[i] != 0xff) {
+ goto nullreturn;
+ }
+ }
+
+ /* Check the last byte in the bitmap. It should contain just the
+ right amount of bits. */
+ if(uip_reassbitmap[uip_reasslen / (8 * 8)] != (u8_t)~bitmap_bits[uip_reasslen / 8 & 7]) {
+ goto nullreturn;
+ }
+
+ /* If we have come this far, we have a full packet in the
+ buffer, so we allocate a pbuf and copy the packet into it. We
+ also reset the timer. */
+ uip_reasstmr = 0;
+ memcpy(BUF, FBUF, uip_reasslen);
+
+ /* Pretend to be a "normal" (i.e., not fragmented) IP packet
+ from now on. */
+ BUF->ipoffset[0] = BUF->ipoffset[1] = 0;
+ BUF->len[0] = uip_reasslen >> 8;
+ BUF->len[1] = uip_reasslen & 0xff;
+ BUF->ipchksum = 0;
+ BUF->ipchksum = ~(uip_ipchksum());
+
+ return uip_reasslen;
+ }
+ }
+
+nullreturn:
+ return 0;
+}
+#endif /* UIP_REASSEMBLY */
+
+/*---------------------------------------------------------------------------*/
+static void uip_add_rcv_nxt(u16_t n) {
+ uip_add32(uip_conn->rcv_nxt, n);
+ uip_conn->rcv_nxt[0] = uip_acc32[0];
+ uip_conn->rcv_nxt[1] = uip_acc32[1];
+ uip_conn->rcv_nxt[2] = uip_acc32[2];
+ uip_conn->rcv_nxt[3] = uip_acc32[3];
+}
+
+/*---------------------------------------------------------------------------*/
+void uip_process(u8_t flag) {
+ register struct uip_conn* uip_connr = uip_conn;
+
+#if UIP_UDP
+ if(flag == UIP_UDP_SEND_CONN) {
+ goto udp_send;
+ }
+#endif /* UIP_UDP */
+
+ uip_sappdata = uip_appdata = &uip_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN];
+
+ /* Check if we were invoked because of a poll request for a
+ particular connection. */
+ if(flag == UIP_POLL_REQUEST) {
+ if((uip_connr->tcpstateflags & UIP_TS_MASK) == UIP_ESTABLISHED && !uip_outstanding(uip_connr)) {
+ uip_flags = UIP_POLL;
+ UIP_APPCALL();
+ goto appsend;
+ }
+
+ goto drop;
+
+ /* Check if we were invoked because of the perodic timer fireing. */
+ }
+ else
+ if(flag == UIP_TIMER)
+ {
+#if UIP_REASSEMBLY
+ if(uip_reasstmr != 0) {
+ --uip_reasstmr;
+ }
+#endif /* UIP_REASSEMBLY */
+
+ /* Increase the initial sequence number. */
+
+ if(++iss[3] == 0) {
+ if(++iss[2] == 0) {
+ if(++iss[1] == 0) {
+ ++iss[0];
+ }
+ }
+ }
+
+ /* Reset the length variables. */
+ uip_len = 0;
+ uip_slen = 0;
+
+ /* Check if the connection is in a state in which we simply wait
+ for the connection to time out. If so, we increase the
+ connection's timer and remove the connection if it times
+ out. */
+ if(uip_connr->tcpstateflags == UIP_TIME_WAIT || uip_connr->tcpstateflags == UIP_FIN_WAIT_2) {
+ ++(uip_connr->timer);
+ if(uip_connr->timer == UIP_TIME_WAIT_TIMEOUT) {
+ uip_connr->tcpstateflags = UIP_CLOSED;
+ }
+ }
+ else
+ if(uip_connr->tcpstateflags != UIP_CLOSED) {
+
+ /* If the connection has outstanding data, we increase the
+ connection's timer and see if it has reached the RTO value
+ in which case we retransmit. */
+ if(uip_outstanding(uip_connr)) {
+ if(uip_connr->timer-- == 0) {
+ if
+ (
+ uip_connr->nrtx == UIP_MAXRTX
+ || (
+ (uip_connr->tcpstateflags == UIP_SYN_SENT || uip_connr->tcpstateflags == UIP_SYN_RCVD)
+ && uip_connr->nrtx == UIP_MAXSYNRTX
+ )
+ ) {
+ uip_connr->tcpstateflags = UIP_CLOSED;
+
+ /* We call UIP_APPCALL() with uip_flags set to
+ UIP_TIMEDOUT to inform the application that the
+ connection has timed out. */
+ uip_flags = UIP_TIMEDOUT;
+ UIP_APPCALL();
+
+ /* We also send a reset packet to the remote host. */
+ BUF->flags = TCP_RST | TCP_ACK;
+ goto tcp_send_nodata;
+ }
+
+ /* Exponential backoff. */
+ uip_connr->timer = UIP_RTO << (uip_connr->nrtx > 4 ? 4 : uip_connr->nrtx);
+ ++(uip_connr->nrtx);
+
+ /* Ok, so we need to retransmit. We do this differently
+ depending on which state we are in. In ESTABLISHED, we
+ call upon the application so that it may prepare the
+ data for the retransmit. In SYN_RCVD, we resend the
+ SYNACK that we sent earlier and in LAST_ACK we have to
+ retransmit our FINACK. */
+ UIP_STAT(++uip_stat.tcp.rexmit);
+ switch(uip_connr->tcpstateflags & UIP_TS_MASK) {
+ case UIP_SYN_RCVD:
+ /* In the SYN_RCVD state, we should retransmit our
+ SYNACK. */
+ goto tcp_send_synack;
+
+#if UIP_ACTIVE_OPEN
+
+ case UIP_SYN_SENT:
+ /* In the SYN_SENT state, we retransmit out SYN. */
+ BUF->flags = 0;
+ goto tcp_send_syn;
+#endif /* UIP_ACTIVE_OPEN */
+
+ case UIP_ESTABLISHED:
+ /* In the ESTABLISHED state, we call upon the application
+ to do the actual retransmit after which we jump into
+ the code for sending out the packet (the apprexmit
+ label). */
+ uip_flags = UIP_REXMIT;
+ UIP_APPCALL();
+ goto apprexmit;
+
+ case UIP_FIN_WAIT_1:
+ case UIP_CLOSING:
+ case UIP_LAST_ACK:
+ /* In all these states we should retransmit a FINACK. */
+ goto tcp_send_finack;
+ }
+ }
+ }
+ else
+ if((uip_connr->tcpstateflags & UIP_TS_MASK) == UIP_ESTABLISHED) {
+
+ /* If there was no need for a retransmission, we poll the
+ application for new data. */
+ uip_flags = UIP_POLL;
+ UIP_APPCALL();
+ goto appsend;
+ }
+ }
+
+ goto drop;
+ }
+
+#if UIP_UDP
+ if(flag == UIP_UDP_TIMER) {
+ if(uip_udp_conn->lport != 0) {
+ uip_conn = NULL;
+ uip_sappdata = uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
+ uip_len = uip_slen = 0;
+ uip_flags = UIP_POLL;
+ UIP_UDP_APPCALL();
+ goto udp_send;
+ }
+ else {
+ goto drop;
+ }
+ }
+#endif
+ /* This is where the input processing starts. */
+
+ UIP_STAT(++uip_stat.ip.recv);
+
+ /* Start of IP input header processing code. */
+#if UIP_CONF_IPV6
+ /* Check validity of the IP header. */
+
+ if((BUF->vtc & 0xf0) != 0x60) {
+
+ /* IP version and header length. */
+ UIP_STAT(++uip_stat.ip.drop);
+ UIP_STAT(++uip_stat.ip.vhlerr);
+ UIP_LOG("ipv6: invalid version.");
+ goto drop;
+ }
+
+#else /* UIP_CONF_IPV6 */
+ /* Check validity of the IP header. */
+
+ if(BUF->vhl != 0x45) {
+
+ /* IP version and header length. */
+ UIP_STAT(++uip_stat.ip.drop);
+ UIP_STAT(++uip_stat.ip.vhlerr);
+ UIP_LOG("ip: invalid version or header length.");
+ goto drop;
+ }
+#endif /* UIP_CONF_IPV6 */
+
+ /* Check the size of the packet. If the size reported to us in
+ uip_len is smaller the size reported in the IP header, we assume
+ that the packet has been corrupted in transit. If the size of
+ uip_len is larger than the size reported in the IP packet header,
+ the packet has been padded and we set uip_len to the correct
+ value.. */
+
+ if((BUF->len[0] << 8) + BUF->len[1] <= uip_len) {
+ uip_len = (BUF->len[0] << 8) + BUF->len[1];
+#if UIP_CONF_IPV6
+ uip_len += 40; /* The length reported in the IPv6 header is the
+ length of the payload that follows the
+ header. However, uIP uses the uip_len variable
+ for holding the size of the entire packet,
+ including the IP header. For IPv4 this is not a
+ problem as the length field in the IPv4 header
+ contains the length of the entire packet. But
+ for IPv6 we need to add the size of the IPv6
+ header (40 bytes). */
+#endif /* UIP_CONF_IPV6 */
+ }
+ else {
+ UIP_LOG("ip: packet shorter than reported in IP header.");
+ goto drop;
+ }
+
+#if !UIP_CONF_IPV6
+ /* Check the fragment flag. */
+
+ if((BUF->ipoffset[0] & 0x3f) != 0 || BUF->ipoffset[1] != 0)
+ {
+ #if UIP_REASSEMBLY
+ uip_len = uip_reass();
+ if(uip_len == 0) {
+ goto drop;
+ }
+
+ #else /* UIP_REASSEMBLY */
+ UIP_STAT(++uip_stat.ip.drop);
+ UIP_STAT(++uip_stat.ip.fragerr);
+ UIP_LOG("ip: fragment dropped.");
+ goto drop;
+ #endif /* UIP_REASSEMBLY */
+ }
+#endif /* UIP_CONF_IPV6 */
+
+ if(uip_ipaddr_cmp(uip_hostaddr, all_zeroes_addr))
+ {
+ /* If we are configured to use ping IP address configuration and
+ hasn't been assigned an IP address yet, we accept all ICMP
+ packets. */
+#if UIP_PINGADDRCONF && !UIP_CONF_IPV6
+ if(BUF->proto == UIP_PROTO_ICMP) {
+ UIP_LOG("ip: possible ping config packet received.");
+ goto icmp_input;
+ }
+ else {
+ UIP_LOG("ip: packet dropped since no address assigned.");
+ goto drop;
+ }
+#endif /* UIP_PINGADDRCONF */
+ }
+ else
+ {
+ /* If IP broadcast support is configured, we check for a broadcast
+ UDP packet, which may be destined to us. */
+#if UIP_BROADCAST
+ DEBUG_PRINTF("UDP IP checksum 0x%04x\n", uip_ipchksum());
+ if
+ (
+ BUF->proto == UIP_PROTO_UDP
+ && uip_ipaddr_cmp(BUF->destipaddr, all_ones_addr) /*&&
+ uip_ipchksum() == 0xffff*/
+ ) {
+ goto udp_input;
+ }
+#endif /* UIP_BROADCAST */
+
+ /* Check if the packet is destined for our IP address. */
+
+#if !UIP_CONF_IPV6
+ if(!uip_ipaddr_cmp(BUF->destipaddr, uip_hostaddr)) {
+ UIP_STAT(++uip_stat.ip.drop);
+ goto drop;
+ }
+
+#else /* UIP_CONF_IPV6 */
+ /* For IPv6, packet reception is a little trickier as we need to
+ make sure that we listen to certain multicast addresses (all
+ hosts multicast address, and the solicited-node multicast
+ address) as well. However, we will cheat here and accept all
+ multicast packets that are sent to the ff02::/16 addresses. */
+
+ if(!uip_ipaddr_cmp(BUF->destipaddr, uip_hostaddr) && BUF->destipaddr[0] != HTONS(0xff02)) {
+ UIP_STAT(++uip_stat.ip.drop);
+ goto drop;
+ }
+#endif /* UIP_CONF_IPV6 */
+ }
+
+#if !UIP_CONF_IPV6
+ if(uip_ipchksum() != 0xffff) {
+
+ /* Compute and check the IP header
+ checksum. */
+ UIP_STAT(++uip_stat.ip.drop);
+ UIP_STAT(++uip_stat.ip.chkerr);
+ UIP_LOG("ip: bad checksum.");
+ goto drop;
+ }
+#endif /* UIP_CONF_IPV6 */
+
+ if(BUF->proto == UIP_PROTO_TCP) {
+
+ /* Check for TCP packet. If so,
+ proceed with TCP input
+ processing. */
+ goto tcp_input;
+ }
+
+#if UIP_UDP
+ if(BUF->proto == UIP_PROTO_UDP) {
+ goto udp_input;
+ }
+#endif /* UIP_UDP */
+
+#if !UIP_CONF_IPV6
+ /* ICMPv4 processing code follows. */
+
+ if(BUF->proto != UIP_PROTO_ICMP) {
+
+ /* We only allow ICMP packets from
+ here. */
+ UIP_STAT(++uip_stat.ip.drop);
+ UIP_STAT(++uip_stat.ip.protoerr);
+ UIP_LOG("ip: neither tcp nor icmp.");
+ goto drop;
+ }
+
+ #if UIP_PINGADDRCONF
+ icmp_input :
+ #endif /* UIP_PINGADDRCONF */
+
+ UIP_STAT(++uip_stat.icmp.recv);
+
+ /* ICMP echo (i.e., ping) processing. This is simple, we only change
+ the ICMP type from ECHO to ECHO_REPLY and adjust the ICMP
+ checksum before we return the packet. */
+ if(ICMPBUF->type != ICMP_ECHO) {
+ UIP_STAT(++uip_stat.icmp.drop);
+ UIP_STAT(++uip_stat.icmp.typeerr);
+ UIP_LOG("icmp: not icmp echo.");
+ goto drop;
+ }
+
+ /* If we are configured to use ping IP address assignment, we use
+ the destination IP address of this ping packet and assign it to
+ ourself. */
+ #if UIP_PINGADDRCONF
+ if((uip_hostaddr[0] | uip_hostaddr[1]) == 0) {
+ uip_hostaddr[0] = BUF->destipaddr[0];
+ uip_hostaddr[1] = BUF->destipaddr[1];
+ }
+ #endif /* UIP_PINGADDRCONF */
+
+ ICMPBUF->type = ICMP_ECHO_REPLY;
+
+ if(ICMPBUF->icmpchksum >= HTONS(0xffff - (ICMP_ECHO << 8))) {
+ ICMPBUF->icmpchksum += HTONS(ICMP_ECHO << 8) + 1;
+ }
+ else {
+ ICMPBUF->icmpchksum += HTONS(ICMP_ECHO << 8);
+ }
+
+ /* Swap IP addresses. */
+ uip_ipaddr_copy(BUF->destipaddr, BUF->srcipaddr);
+ uip_ipaddr_copy(BUF->srcipaddr, uip_hostaddr);
+
+ UIP_STAT(++uip_stat.icmp.sent);
+ goto send;
+
+ /* End of IPv4 input header processing code. */
+#else /* !UIP_CONF_IPV6 */
+ /* This is IPv6 ICMPv6 processing code. */
+
+ DEBUG_PRINTF("icmp6_input: length %d\n", uip_len);
+
+ if(BUF->proto != UIP_PROTO_ICMP6) {
+
+ /* We only allow ICMPv6 packets from
+ here. */
+ UIP_STAT(++uip_stat.ip.drop);
+ UIP_STAT(++uip_stat.ip.protoerr);
+ UIP_LOG("ip: neither tcp nor icmp6.");
+ goto drop;
+ }
+
+ UIP_STAT(++uip_stat.icmp.recv);
+
+ /* If we get a neighbor solicitation for our address we should send
+ a neighbor advertisement message back. */
+ if(ICMPBUF->type == ICMP6_NEIGHBOR_SOLICITATION) {
+ if(uip_ipaddr_cmp(ICMPBUF->icmp6data, uip_hostaddr)) {
+ if(ICMPBUF->options[0] == ICMP6_OPTION_SOURCE_LINK_ADDRESS) {
+
+ /* Save the sender's address in our neighbor list. */
+ uip_neighbor_add(ICMPBUF->srcipaddr, &(ICMPBUF->options[2]));
+ }
+
+ /* We should now send a neighbor advertisement back to where the
+ neighbor solicication came from. */
+ ICMPBUF->type = ICMP6_NEIGHBOR_ADVERTISEMENT;
+ ICMPBUF->flags = ICMP6_FLAG_S; /* Solicited flag. */
+
+ ICMPBUF->reserved1 = ICMPBUF->reserved2 = ICMPBUF->reserved3 = 0;
+
+ uip_ipaddr_copy(ICMPBUF->destipaddr, ICMPBUF->srcipaddr);
+ uip_ipaddr_copy(ICMPBUF->srcipaddr, uip_hostaddr);
+ ICMPBUF->options[0] = ICMP6_OPTION_TARGET_LINK_ADDRESS;
+ ICMPBUF->options[1] = 1; /* Options length, 1 = 8 bytes. */
+ memcpy(&(ICMPBUF->options[2]), &uip_ethaddr, sizeof(uip_ethaddr));
+ ICMPBUF->icmpchksum = 0;
+ ICMPBUF->icmpchksum = ~uip_icmp6chksum();
+ goto send;
+ }
+
+ goto drop;
+ }
+ else
+ if(ICMPBUF->type == ICMP6_ECHO) {
+
+ /* ICMP echo (i.e., ping) processing. This is simple, we only
+ change the ICMP type from ECHO to ECHO_REPLY and update the
+ ICMP checksum before we return the packet. */
+ ICMPBUF->type = ICMP6_ECHO_REPLY;
+
+ uip_ipaddr_copy(BUF->destipaddr, BUF->srcipaddr);
+ uip_ipaddr_copy(BUF->srcipaddr, uip_hostaddr);
+ ICMPBUF->icmpchksum = 0;
+ ICMPBUF->icmpchksum = ~uip_icmp6chksum();
+
+ UIP_STAT(++uip_stat.icmp.sent);
+ goto send;
+ }
+ else {
+ DEBUG_PRINTF("Unknown icmp6 message type %d\n", ICMPBUF->type);
+ UIP_STAT(++uip_stat.icmp.drop);
+ UIP_STAT(++uip_stat.icmp.typeerr);
+ UIP_LOG("icmp: unknown ICMP message.");
+ goto drop;
+ }
+
+ /* End of IPv6 ICMP processing. */
+#endif /* !UIP_CONF_IPV6 */
+
+#if UIP_UDP
+ /* UDP input processing. */
+
+ udp_input :
+ /* UDP processing is really just a hack. We don't do anything to the
+ UDP/IP headers, but let the UDP application do all the hard
+ work. If the application sets uip_slen, it has a packet to
+ send. */
+ #if UIP_UDP_CHECKSUMS
+ uip_len = uip_len - UIP_IPUDPH_LEN;
+ uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
+ if(UDPBUF->udpchksum != 0 && uip_udpchksum() != 0xffff) {
+ UIP_STAT(++uip_stat.udp.drop);
+ UIP_STAT(++uip_stat.udp.chkerr);
+ UIP_LOG("udp: bad checksum.");
+ goto drop;
+ }
+
+ #else /* UIP_UDP_CHECKSUMS */
+ uip_len = uip_len - UIP_IPUDPH_LEN;
+ #endif /* UIP_UDP_CHECKSUMS */
+
+ /* Demultiplex this UDP packet between the UDP "connections". */
+
+ for(uip_udp_conn = &uip_udp_conns[0]; uip_udp_conn < &uip_udp_conns[UIP_UDP_CONNS]; ++uip_udp_conn) {
+
+ /* If the local UDP port is non-zero, the connection is considered
+ to be used. If so, the local port number is checked against the
+ destination port number in the received packet. If the two port
+ numbers match, the remote port number is checked if the
+ connection is bound to a remote port. Finally, if the
+ connection is bound to a remote IP address, the source IP
+ address of the packet is checked. */
+ if
+ (
+ uip_udp_conn->lport != 0
+ && UDPBUF->destport == uip_udp_conn->lport
+ && (uip_udp_conn->rport == 0 || UDPBUF->srcport == uip_udp_conn->rport)
+ && (
+ uip_ipaddr_cmp(uip_udp_conn->ripaddr, all_zeroes_addr)
+ || uip_ipaddr_cmp(uip_udp_conn->ripaddr, all_ones_addr)
+ || uip_ipaddr_cmp(BUF->srcipaddr, uip_udp_conn->ripaddr)
+ )
+ ) {
+ goto udp_found;
+ }
+ }
+
+ UIP_LOG("udp: no matching connection found");
+ goto drop;
+
+udp_found:
+ uip_conn = NULL;
+ uip_flags = UIP_NEWDATA;
+ uip_sappdata = uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
+ uip_slen = 0;
+ UIP_UDP_APPCALL();
+udp_send:
+ if(uip_slen == 0) {
+ goto drop;
+ }
+
+ uip_len = uip_slen + UIP_IPUDPH_LEN;
+
+ #if UIP_CONF_IPV6
+ /* For IPv6, the IP length field does not include the IPv6 IP header
+ length. */
+
+ BUF->len[0] = ((uip_len - UIP_IPH_LEN) >> 8);
+ BUF->len[1] = ((uip_len - UIP_IPH_LEN) & 0xff);
+ #else /* UIP_CONF_IPV6 */
+ BUF->len[0] = (uip_len >> 8);
+ BUF->len[1] = (uip_len & 0xff);
+ #endif /* UIP_CONF_IPV6 */
+
+ BUF->ttl = uip_udp_conn->ttl;
+ BUF->proto = UIP_PROTO_UDP;
+
+ UDPBUF->udplen = HTONS(uip_slen + UIP_UDPH_LEN);
+ UDPBUF->udpchksum = 0;
+
+ BUF->srcport = uip_udp_conn->lport;
+ BUF->destport = uip_udp_conn->rport;
+
+ uip_ipaddr_copy(BUF->srcipaddr, uip_hostaddr);
+ uip_ipaddr_copy(BUF->destipaddr, uip_udp_conn->ripaddr);
+
+ uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPTCPH_LEN];
+
+ #if UIP_UDP_CHECKSUMS
+ /* Calculate UDP checksum. */
+
+ UDPBUF->udpchksum = ~(uip_udpchksum());
+ if(UDPBUF->udpchksum == 0) {
+ UDPBUF->udpchksum = 0xffff;
+ }
+ #endif /* UIP_UDP_CHECKSUMS */
+
+ goto ip_send_nolen;
+#endif /* UIP_UDP */
+
+ /* TCP input processing. */
+
+ tcp_input : UIP_STAT(++uip_stat.tcp.recv);
+
+ /* Start of TCP input header processing code. */
+ if(uip_tcpchksum() != 0xffff) {
+
+ /* Compute and check the TCP
+ checksum. */
+ UIP_STAT(++uip_stat.tcp.drop);
+ UIP_STAT(++uip_stat.tcp.chkerr);
+ UIP_LOG("tcp: bad checksum.");
+ goto drop;
+ }
+
+ /* Demultiplex this segment. */
+ /* First check any active connections. */
+ for(uip_connr = &uip_conns[0]; uip_connr <= &uip_conns[UIP_CONNS - 1]; ++uip_connr) {
+ if
+ (
+ uip_connr->tcpstateflags != UIP_CLOSED
+ && BUF->destport == uip_connr->lport
+ && BUF->srcport == uip_connr->rport
+ && uip_ipaddr_cmp(BUF->srcipaddr, uip_connr->ripaddr)
+ ) {
+ goto found;
+ }
+ }
+
+ /* If we didn't find and active connection that expected the packet,
+ either this packet is an old duplicate, or this is a SYN packet
+ destined for a connection in LISTEN. If the SYN flag isn't set,
+ it is an old packet and we send a RST. */
+ if((BUF->flags & TCP_CTL) != TCP_SYN) {
+ goto reset;
+ }
+
+ tmp16 = BUF->destport;
+
+ /* Next, check listening connections. */
+ for(c = 0; c < UIP_LISTENPORTS; ++c) {
+ if(tmp16 == uip_listenports[c])
+ goto found_listen;
+ }
+
+ /* No matching connection found, so we send a RST packet. */
+ UIP_STAT(++uip_stat.tcp.synrst);
+reset:
+ /* We do not send resets in response to resets. */
+ if(BUF->flags & TCP_RST) {
+ goto drop;
+ }
+
+ UIP_STAT(++uip_stat.tcp.rst);
+
+ BUF->flags = TCP_RST | TCP_ACK;
+ uip_len = UIP_IPTCPH_LEN;
+ BUF->tcpoffset = 5 << 4;
+
+ /* Flip the seqno and ackno fields in the TCP header. */
+ c = BUF->seqno[3];
+ BUF->seqno[3] = BUF->ackno[3];
+ BUF->ackno[3] = c;
+
+ c = BUF->seqno[2];
+ BUF->seqno[2] = BUF->ackno[2];
+ BUF->ackno[2] = c;
+
+ c = BUF->seqno[1];
+ BUF->seqno[1] = BUF->ackno[1];
+ BUF->ackno[1] = c;
+
+ c = BUF->seqno[0];
+ BUF->seqno[0] = BUF->ackno[0];
+ BUF->ackno[0] = c;
+
+ /* We also have to increase the sequence number we are
+ acknowledging. If the least significant byte overflowed, we need
+ to propagate the carry to the other bytes as well. */
+ if(++BUF->ackno[3] == 0) {
+ if(++BUF->ackno[2] == 0) {
+ if(++BUF->ackno[1] == 0) {
+ ++BUF->ackno[0];
+ }
+ }
+ }
+
+ /* Swap port numbers. */
+ tmp16 = BUF->srcport;
+ BUF->srcport = BUF->destport;
+ BUF->destport = tmp16;
+
+ /* Swap IP addresses. */
+ uip_ipaddr_copy(BUF->destipaddr, BUF->srcipaddr);
+ uip_ipaddr_copy(BUF->srcipaddr, uip_hostaddr);
+
+ /* And send out the RST packet! */
+ goto tcp_send_noconn;
+
+ /* This label will be jumped to if we matched the incoming packet
+ with a connection in LISTEN. In that case, we should create a new
+ connection and send a SYNACK in return. */
+found_listen:
+ /* First we check if there are any connections avaliable. Unused
+ connections are kept in the same table as used connections, but
+ unused ones have the tcpstate set to CLOSED. Also, connections in
+ TIME_WAIT are kept track of and we'll use the oldest one if no
+ CLOSED connections are found. Thanks to Eddie C. Dost for a very
+ nice algorithm for the TIME_WAIT search. */
+ uip_connr = 0;
+ for(c = 0; c < UIP_CONNS; ++c) {
+ if(uip_conns[c].tcpstateflags == UIP_CLOSED) {
+ uip_connr = &uip_conns[c];
+ break;
+ }
+
+ if(uip_conns[c].tcpstateflags == UIP_TIME_WAIT) {
+ if(uip_connr == 0 || uip_conns[c].timer > uip_connr->timer) {
+ uip_connr = &uip_conns[c];
+ }
+ }
+ }
+
+ if(uip_connr == 0) {
+
+ /* All connections are used already, we drop packet and hope that
+ the remote end will retransmit the packet at a time when we
+ have more spare connections. */
+ UIP_STAT(++uip_stat.tcp.syndrop);
+ UIP_LOG("tcp: found no unused connections.");
+ goto drop;
+ }
+
+ uip_conn = uip_connr;
+
+ /* Fill in the necessary fields for the new connection. */
+ uip_connr->rto = uip_connr->timer = UIP_RTO;
+ uip_connr->sa = 0;
+ uip_connr->sv = 4;
+ uip_connr->nrtx = 0;
+ uip_connr->lport = BUF->destport;
+ uip_connr->rport = BUF->srcport;
+ uip_ipaddr_copy(uip_connr->ripaddr, BUF->srcipaddr);
+ uip_connr->tcpstateflags = UIP_SYN_RCVD;
+
+ uip_connr->snd_nxt[0] = iss[0];
+ uip_connr->snd_nxt[1] = iss[1];
+ uip_connr->snd_nxt[2] = iss[2];
+ uip_connr->snd_nxt[3] = iss[3];
+ uip_connr->len = 1;
+
+ /* rcv_nxt should be the seqno from the incoming packet + 1. */
+ uip_connr->rcv_nxt[3] = BUF->seqno[3];
+ uip_connr->rcv_nxt[2] = BUF->seqno[2];
+ uip_connr->rcv_nxt[1] = BUF->seqno[1];
+ uip_connr->rcv_nxt[0] = BUF->seqno[0];
+ uip_add_rcv_nxt(1);
+
+ /* Parse the TCP MSS option, if present. */
+ if((BUF->tcpoffset & 0xf0) > 0x50) {
+ for(c = 0; c < ((BUF->tcpoffset >> 4) - 5) << 2;) {
+ opt = uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + c];
+ if(opt == TCP_OPT_END) {
+
+ /* End of options. */
+ break;
+ }
+ else
+ if(opt == TCP_OPT_NOOP) {
+ ++c;
+
+ /* NOP option. */
+ }
+ else
+ if(opt == TCP_OPT_MSS && uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == TCP_OPT_MSS_LEN) {
+
+ /* An MSS option with the right option length. */
+ tmp16 = ((u16_t) uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) | (u16_t) uip_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN + 3 + c];
+ uip_connr->initialmss = uip_connr->mss = tmp16 > UIP_TCP_MSS ? UIP_TCP_MSS : tmp16;
+
+ /* And we are done processing options. */
+ break;
+ }
+ else {
+
+ /* All other options have a length field, so that we easily
+ can skip past them. */
+ if(uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0) {
+
+ /* If the length field is zero, the options are malformed
+ and we don't process them further. */
+ break;
+ }
+
+ c += uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c];
+ }
+ }
+ }
+
+ /* Our response will be a SYNACK. */
+#if UIP_ACTIVE_OPEN
+ tcp_send_synack : BUF->flags = TCP_ACK;
+
+tcp_send_syn:
+ BUF->flags |= TCP_SYN;
+#else /* UIP_ACTIVE_OPEN */
+ tcp_send_synack : BUF->flags = TCP_SYN | TCP_ACK;
+#endif /* UIP_ACTIVE_OPEN */
+
+ /* We send out the TCP Maximum Segment Size option with our
+ SYNACK. */
+
+ BUF->optdata[0] = TCP_OPT_MSS;
+ BUF->optdata[1] = TCP_OPT_MSS_LEN;
+ BUF->optdata[2] = (UIP_TCP_MSS) / 256;
+ BUF->optdata[3] = (UIP_TCP_MSS) & 255;
+ uip_len = UIP_IPTCPH_LEN + TCP_OPT_MSS_LEN;
+ BUF->tcpoffset = ((UIP_TCPH_LEN + TCP_OPT_MSS_LEN) / 4) << 4;
+ goto tcp_send;
+
+ /* This label will be jumped to if we found an active connection. */
+found:
+ uip_conn = uip_connr;
+ uip_flags = 0;
+
+ /* We do a very naive form of TCP reset processing; we just accept
+ any RST and kill our connection. We should in fact check if the
+ sequence number of this reset is wihtin our advertised window
+ before we accept the reset. */
+ if(BUF->flags & TCP_RST) {
+ uip_connr->tcpstateflags = UIP_CLOSED;
+ UIP_LOG("tcp: got reset, aborting connection.");
+ uip_flags = UIP_ABORT;
+ UIP_APPCALL();
+ goto drop;
+ }
+
+ /* Calculated the length of the data, if the application has sent
+ any data to us. */
+ c = (BUF->tcpoffset >> 4) << 2;
+
+ /* uip_len will contain the length of the actual TCP data. This is
+ calculated by subtracing the length of the TCP header (in
+ c) and the length of the IP header (20 bytes). */
+ uip_len = uip_len - c - UIP_IPH_LEN;
+
+ /* First, check if the sequence number of the incoming packet is
+ what we're expecting next. If not, we send out an ACK with the
+ correct numbers in. */
+ if(!(((uip_connr->tcpstateflags & UIP_TS_MASK) == UIP_SYN_SENT) && ((BUF->flags & TCP_CTL) == (TCP_SYN | TCP_ACK)))) {
+ if
+ (
+ (uip_len > 0 || ((BUF->flags & (TCP_SYN | TCP_FIN)) != 0))
+ && (
+ BUF->seqno[0] != uip_connr->rcv_nxt[0]
+ || BUF->seqno[1] != uip_connr->rcv_nxt[1]
+ || BUF->seqno[2] != uip_connr->rcv_nxt[2]
+ || BUF->seqno[3] != uip_connr->rcv_nxt[3]
+ )
+ ) {
+ goto tcp_send_ack;
+ }
+ }
+
+ /* Next, check if the incoming segment acknowledges any outstanding
+ data. If so, we update the sequence number, reset the length of
+ the outstanding data, calculate RTT estimations, and reset the
+ retransmission timer. */
+ if((BUF->flags & TCP_ACK) && uip_outstanding(uip_connr)) {
+ uip_add32(uip_connr->snd_nxt, uip_connr->len);
+
+ if
+ (
+ BUF->ackno[0] == uip_acc32[0]
+ && BUF->ackno[1] == uip_acc32[1]
+ && BUF->ackno[2] == uip_acc32[2]
+ && BUF->ackno[3] == uip_acc32[3]
+ ) {
+
+ /* Update sequence number. */
+ uip_connr->snd_nxt[0] = uip_acc32[0];
+ uip_connr->snd_nxt[1] = uip_acc32[1];
+ uip_connr->snd_nxt[2] = uip_acc32[2];
+ uip_connr->snd_nxt[3] = uip_acc32[3];
+
+ /* Do RTT estimation, unless we have done retransmissions. */
+ if(uip_connr->nrtx == 0) {
+ signed char m;
+ m = uip_connr->rto - uip_connr->timer;
+
+ /* This is taken directly from VJs original code in his paper */
+ m = m - (uip_connr->sa >> 3);
+ uip_connr->sa += m;
+ if(m < 0) {
+ m = -m;
+ }
+
+ m = m - (uip_connr->sv >> 2);
+ uip_connr->sv += m;
+ uip_connr->rto = (uip_connr->sa >> 3) + uip_connr->sv;
+ }
+
+ /* Set the acknowledged flag. */
+ uip_flags = UIP_ACKDATA;
+
+ /* Reset the retransmission timer. */
+ uip_connr->timer = uip_connr->rto;
+
+ /* Reset length of outstanding data. */
+ uip_connr->len = 0;
+ }
+ }
+
+ /* Do different things depending on in what state the connection is. */
+ switch(uip_connr->tcpstateflags & UIP_TS_MASK) {
+ /* CLOSED and LISTEN are not handled here. CLOSE_WAIT is not
+ implemented, since we force the application to close when the
+ peer sends a FIN (hence the application goes directly from
+ ESTABLISHED to LAST_ACK). */
+ case UIP_SYN_RCVD:
+ /* In SYN_RCVD we have sent out a SYNACK in response to a SYN, and
+ we are waiting for an ACK that acknowledges the data we sent
+ out the last time. Therefore, we want to have the UIP_ACKDATA
+ flag set. If so, we enter the ESTABLISHED state. */
+ if(uip_flags & UIP_ACKDATA) {
+ uip_connr->tcpstateflags = UIP_ESTABLISHED;
+ uip_flags = UIP_CONNECTED;
+ uip_connr->len = 0;
+ if(uip_len > 0) {
+ uip_flags |= UIP_NEWDATA;
+ uip_add_rcv_nxt(uip_len);
+ }
+
+ uip_slen = 0;
+ UIP_APPCALL();
+ goto appsend;
+ }
+
+ goto drop;
+#if UIP_ACTIVE_OPEN
+
+ case UIP_SYN_SENT:
+ /* In SYN_SENT, we wait for a SYNACK that is sent in response to
+ our SYN. The rcv_nxt is set to sequence number in the SYNACK
+ plus one, and we send an ACK. We move into the ESTABLISHED
+ state. */
+ if((uip_flags & UIP_ACKDATA) && (BUF->flags & TCP_CTL) == (TCP_SYN | TCP_ACK)) {
+
+ /* Parse the TCP MSS option, if present. */
+ if((BUF->tcpoffset & 0xf0) > 0x50) {
+ for(c = 0; c < ((BUF->tcpoffset >> 4) - 5) << 2;) {
+ opt = uip_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN + c];
+ if(opt == TCP_OPT_END) {
+
+ /* End of options. */
+ break;
+ }
+ else
+ if(opt == TCP_OPT_NOOP) {
+ ++c;
+
+ /* NOP option. */
+ }
+ else
+ if(opt == TCP_OPT_MSS && uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == TCP_OPT_MSS_LEN) {
+
+ /* An MSS option with the right option length. */
+ tmp16 = (uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) | uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 3 + c];
+ uip_connr->initialmss = uip_connr->mss = tmp16 > UIP_TCP_MSS ? UIP_TCP_MSS : tmp16;
+
+ /* And we are done processing options. */
+ break;
+ }
+ else {
+
+ /* All other options have a length field, so that we easily
+ can skip past them. */
+ if(uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0) {
+
+ /* If the length field is zero, the options are malformed
+ and we don't process them further. */
+ break;
+ }
+
+ c += uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c];
+ }
+ }
+ }
+
+ uip_connr->tcpstateflags = UIP_ESTABLISHED;
+ uip_connr->rcv_nxt[0] = BUF->seqno[0];
+ uip_connr->rcv_nxt[1] = BUF->seqno[1];
+ uip_connr->rcv_nxt[2] = BUF->seqno[2];
+ uip_connr->rcv_nxt[3] = BUF->seqno[3];
+ uip_add_rcv_nxt(1);
+ uip_flags = UIP_CONNECTED | UIP_NEWDATA;
+ uip_connr->len = 0;
+ uip_len = 0;
+ uip_slen = 0;
+ UIP_APPCALL();
+ goto appsend;
+ }
+
+ /* Inform the application that the connection failed */
+ uip_flags = UIP_ABORT;
+ UIP_APPCALL();
+
+ /* The connection is closed after we send the RST */
+ uip_conn->tcpstateflags = UIP_CLOSED;
+ goto reset;
+#endif /* UIP_ACTIVE_OPEN */
+
+ case UIP_ESTABLISHED:
+ /* In the ESTABLISHED state, we call upon the application to feed
+ data into the uip_buf. If the UIP_ACKDATA flag is set, the
+ application should put new data into the buffer, otherwise we are
+ retransmitting an old segment, and the application should put that
+ data into the buffer.
+
+ If the incoming packet is a FIN, we should close the connection on
+ this side as well, and we send out a FIN and enter the LAST_ACK
+ state. We require that there is no outstanding data; otherwise the
+ sequence numbers will be screwed up. */
+ if(BUF->flags & TCP_FIN && !(uip_connr->tcpstateflags & UIP_STOPPED)) {
+ if(uip_outstanding(uip_connr)) {
+ goto drop;
+ }
+
+ uip_add_rcv_nxt(1 + uip_len);
+ uip_flags |= UIP_CLOSE;
+ if(uip_len > 0) {
+ uip_flags |= UIP_NEWDATA;
+ }
+
+ UIP_APPCALL();
+ uip_connr->len = 1;
+ uip_connr->tcpstateflags = UIP_LAST_ACK;
+ uip_connr->nrtx = 0;
+tcp_send_finack:
+ BUF->flags = TCP_FIN | TCP_ACK;
+ goto tcp_send_nodata;
+ }
+
+ /* Check the URG flag. If this is set, the segment carries urgent
+ data that we must pass to the application. */
+ if((BUF->flags & TCP_URG) != 0)
+ {
+#if UIP_URGDATA > 0
+ uip_urglen = (BUF->urgp[0] << 8) | BUF->urgp[1];
+ if(uip_urglen > uip_len) {
+
+ /* There is more urgent data in the next segment to come. */
+ uip_urglen = uip_len;
+ }
+
+ uip_add_rcv_nxt(uip_urglen);
+ uip_len -= uip_urglen;
+ uip_urgdata = uip_appdata;
+ uip_appdata += uip_urglen;
+ }
+ else {
+ uip_urglen = 0;
+#else /* UIP_URGDATA > 0 */
+ uip_appdata = ((char*)uip_appdata) + ((BUF->urgp[0] << 8) | BUF->urgp[1]);
+ uip_len -= (BUF->urgp[0] << 8) | BUF->urgp[1];
+#endif /* UIP_URGDATA > 0 */
+ }
+
+ /* If uip_len > 0 we have TCP data in the packet, and we flag this
+ by setting the UIP_NEWDATA flag and update the sequence number
+ we acknowledge. If the application has stopped the dataflow
+ using uip_stop(), we must not accept any data packets from the
+ remote host. */
+ if(uip_len > 0 && !(uip_connr->tcpstateflags & UIP_STOPPED)) {
+ uip_flags |= UIP_NEWDATA;
+ uip_add_rcv_nxt(uip_len);
+ }
+
+ /* Check if the available buffer space advertised by the other end
+ is smaller than the initial MSS for this connection. If so, we
+ set the current MSS to the window size to ensure that the
+ application does not send more data than the other end can
+ handle.
+
+ If the remote host advertises a zero window, we set the MSS to
+ the initial MSS so that the application will send an entire MSS
+ of data. This data will not be acknowledged by the receiver,
+ and the application will retransmit it. This is called the
+ "persistent timer" and uses the retransmission mechanim.
+ */
+ tmp16 = ((u16_t) BUF->wnd[0] << 8) + (u16_t) BUF->wnd[1];
+ if(tmp16 > uip_connr->initialmss || tmp16 == 0) {
+ tmp16 = uip_connr->initialmss;
+ }
+
+ uip_connr->mss = tmp16;
+
+ /* If this packet constitutes an ACK for outstanding data (flagged
+ by the UIP_ACKDATA flag, we should call the application since it
+ might want to send more data. If the incoming packet had data
+ from the peer (as flagged by the UIP_NEWDATA flag), the
+ application must also be notified.
+
+ When the application is called, the global variable uip_len
+ contains the length of the incoming data. The application can
+ access the incoming data through the global pointer
+ uip_appdata, which usually points UIP_IPTCPH_LEN + UIP_LLH_LEN
+ bytes into the uip_buf array.
+
+ If the application wishes to send any data, this data should be
+ put into the uip_appdata and the length of the data should be
+ put into uip_len. If the application don't have any data to
+ send, uip_len must be set to 0. */
+ if(uip_flags & (UIP_NEWDATA | UIP_ACKDATA)) {
+ uip_slen = 0;
+ UIP_APPCALL();
+
+appsend:
+ if(uip_flags & UIP_ABORT) {
+ uip_slen = 0;
+ uip_connr->tcpstateflags = UIP_CLOSED;
+ BUF->flags = TCP_RST | TCP_ACK;
+ goto tcp_send_nodata;
+ }
+
+ if(uip_flags & UIP_CLOSE) {
+ uip_slen = 0;
+ uip_connr->len = 1;
+ uip_connr->tcpstateflags = UIP_FIN_WAIT_1;
+ uip_connr->nrtx = 0;
+ BUF->flags = TCP_FIN | TCP_ACK;
+ goto tcp_send_nodata;
+ }
+
+ /* If uip_slen > 0, the application has data to be sent. */
+ if(uip_slen > 0) {
+
+ /* If the connection has acknowledged data, the contents of
+ the ->len variable should be discarded. */
+ if((uip_flags & UIP_ACKDATA) != 0) {
+ uip_connr->len = 0;
+ }
+
+ /* If the ->len variable is non-zero the connection has
+ already data in transit and cannot send anymore right
+ now. */
+ if(uip_connr->len == 0) {
+
+ /* The application cannot send more than what is allowed by
+ the mss (the minumum of the MSS and the available
+ window). */
+ if(uip_slen > uip_connr->mss) {
+ uip_slen = uip_connr->mss;
+ }
+
+ /* Remember how much data we send out now so that we know
+ when everything has been acknowledged. */
+ uip_connr->len = uip_slen;
+ }
+ else {
+
+ /* If the application already had unacknowledged data, we
+ make sure that the application does not send (i.e.,
+ retransmit) out more than it previously sent out. */
+ uip_slen = uip_connr->len;
+ }
+ }
+
+ uip_connr->nrtx = 0;
+apprexmit:
+ uip_appdata = uip_sappdata;
+
+ /* If the application has data to be sent, or if the incoming
+ packet had new data in it, we must send out a packet. */
+ if(uip_slen > 0 && uip_connr->len > 0) {
+
+ /* Add the length of the IP and TCP headers. */
+ uip_len = uip_connr->len + UIP_TCPIP_HLEN;
+
+ /* We always set the ACK flag in response packets. */
+ BUF->flags = TCP_ACK | TCP_PSH;
+
+ /* Send the packet. */
+ goto tcp_send_noopts;
+ }
+
+ /* If there is no data to send, just send out a pure ACK if
+ there is newdata. */
+ if(uip_flags & UIP_NEWDATA) {
+ uip_len = UIP_TCPIP_HLEN;
+ BUF->flags = TCP_ACK;
+ goto tcp_send_noopts;
+ }
+ }
+
+ goto drop;
+
+ case UIP_LAST_ACK:
+ /* We can close this connection if the peer has acknowledged our
+ FIN. This is indicated by the UIP_ACKDATA flag. */
+ if(uip_flags & UIP_ACKDATA) {
+ uip_connr->tcpstateflags = UIP_CLOSED;
+ uip_flags = UIP_CLOSE;
+ UIP_APPCALL();
+ }
+ break;
+
+ case UIP_FIN_WAIT_1:
+ /* The application has closed the connection, but the remote host
+ hasn't closed its end yet. Thus we do nothing but wait for a
+ FIN from the other side. */
+ if(uip_len > 0) {
+ uip_add_rcv_nxt(uip_len);
+ }
+
+ if(BUF->flags & TCP_FIN) {
+ if(uip_flags & UIP_ACKDATA) {
+ uip_connr->tcpstateflags = UIP_TIME_WAIT;
+ uip_connr->timer = 0;
+ uip_connr->len = 0;
+ }
+ else {
+ uip_connr->tcpstateflags = UIP_CLOSING;
+ }
+
+ uip_add_rcv_nxt(1);
+ uip_flags = UIP_CLOSE;
+ UIP_APPCALL();
+ goto tcp_send_ack;
+ }
+ else
+ if(uip_flags & UIP_ACKDATA) {
+ uip_connr->tcpstateflags = UIP_FIN_WAIT_2;
+ uip_connr->len = 0;
+ goto drop;
+ }
+
+ if(uip_len > 0) {
+ goto tcp_send_ack;
+ }
+
+ goto drop;
+
+ case UIP_FIN_WAIT_2:
+ if(uip_len > 0) {
+ uip_add_rcv_nxt(uip_len);
+ }
+
+ if(BUF->flags & TCP_FIN) {
+ uip_connr->tcpstateflags = UIP_TIME_WAIT;
+ uip_connr->timer = 0;
+ uip_add_rcv_nxt(1);
+ uip_flags = UIP_CLOSE;
+ UIP_APPCALL();
+ goto tcp_send_ack;
+ }
+
+ if(uip_len > 0) {
+ goto tcp_send_ack;
+ }
+
+ goto drop;
+
+ case UIP_TIME_WAIT:
+ goto tcp_send_ack;
+
+ case UIP_CLOSING:
+ if(uip_flags & UIP_ACKDATA) {
+ uip_connr->tcpstateflags = UIP_TIME_WAIT;
+ uip_connr->timer = 0;
+ }
+ }
+
+ goto drop;
+
+ /* We jump here when we are ready to send the packet, and just want
+ to set the appropriate TCP sequence numbers in the TCP header. */
+tcp_send_ack:
+ BUF->flags = TCP_ACK;
+tcp_send_nodata:
+ uip_len = UIP_IPTCPH_LEN;
+tcp_send_noopts:
+ BUF->tcpoffset = (UIP_TCPH_LEN / 4) << 4;
+tcp_send:
+ /* We're done with the input processing. We are now ready to send a
+ reply. Our job is to fill in all the fields of the TCP and IP
+ headers before calculating the checksum and finally send the
+ packet. */
+ BUF->ackno[0] = uip_connr->rcv_nxt[0];
+ BUF->ackno[1] = uip_connr->rcv_nxt[1];
+ BUF->ackno[2] = uip_connr->rcv_nxt[2];
+ BUF->ackno[3] = uip_connr->rcv_nxt[3];
+
+ BUF->seqno[0] = uip_connr->snd_nxt[0];
+ BUF->seqno[1] = uip_connr->snd_nxt[1];
+ BUF->seqno[2] = uip_connr->snd_nxt[2];
+ BUF->seqno[3] = uip_connr->snd_nxt[3];
+
+ BUF->proto = UIP_PROTO_TCP;
+
+ BUF->srcport = uip_connr->lport;
+ BUF->destport = uip_connr->rport;
+
+ uip_ipaddr_copy(BUF->srcipaddr, uip_hostaddr);
+ uip_ipaddr_copy(BUF->destipaddr, uip_connr->ripaddr);
+
+ if(uip_connr->tcpstateflags & UIP_STOPPED) {
+
+ /* If the connection has issued uip_stop(), we advertise a zero
+ window so that the remote host will stop sending data. */
+ BUF->wnd[0] = BUF->wnd[1] = 0;
+ }
+ else {
+ BUF->wnd[0] = ((UIP_RECEIVE_WINDOW) >> 8);
+ BUF->wnd[1] = ((UIP_RECEIVE_WINDOW) & 0xff);
+ }
+
+tcp_send_noconn:
+ BUF->ttl = UIP_TTL;
+#if UIP_CONF_IPV6
+ /* For IPv6, the IP length field does not include the IPv6 IP header
+ length. */
+
+ BUF->len[0] = ((uip_len - UIP_IPH_LEN) >> 8);
+ BUF->len[1] = ((uip_len - UIP_IPH_LEN) & 0xff);
+#else /* UIP_CONF_IPV6 */
+ BUF->len[0] = (uip_len >> 8);
+ BUF->len[1] = (uip_len & 0xff);
+#endif /* UIP_CONF_IPV6 */
+
+ BUF->urgp[0] = BUF->urgp[1] = 0;
+
+ /* Calculate TCP checksum. */
+ BUF->tcpchksum = 0;
+ BUF->tcpchksum = ~(uip_tcpchksum());
+
+ip_send_nolen:
+#if UIP_CONF_IPV6
+ BUF->vtc = 0x60;
+ BUF->tcflow = 0x00;
+ BUF->flow = 0x00;
+#else /* UIP_CONF_IPV6 */
+ BUF->vhl = 0x45;
+ BUF->tos = 0;
+ BUF->ipoffset[0] = BUF->ipoffset[1] = 0;
+ ++ipid;
+ BUF->ipid[0] = ipid >> 8;
+ BUF->ipid[1] = ipid & 0xff;
+
+ /* Calculate IP checksum. */
+ BUF->ipchksum = 0;
+ BUF->ipchksum = ~(uip_ipchksum());
+ DEBUG_PRINTF("uip ip_send_nolen: chkecum 0x%04x\n", uip_ipchksum());
+#endif /* UIP_CONF_IPV6 */
+
+ UIP_STAT(++uip_stat.tcp.sent);
+send:
+ DEBUG_PRINTF("Sending packet with length %d (%d)\n", uip_len, (BUF->len[0] << 8) | BUF->len[1]);
+
+ UIP_STAT(++uip_stat.ip.sent);
+
+ /* Return and let the caller do the actual transmission. */
+ uip_flags = 0;
+ return;
+drop:
+ uip_len = 0;
+ uip_flags = 0;
+ return;
+}
+
+/*---------------------------------------------------------------------------*/
+u16_t htons(u16_t val) {
+ return HTONS(val);
+}
+
+/*---------------------------------------------------------------------------*/
+void uip_send(const void* data, int len) {
+ uip_slen = len;
+ if(len > 0) {
+ if(data != uip_sappdata) {
+ memcpy(uip_sappdata, (data), uip_slen);
+ }
+ }
+}
+
+/** @} */